I have developed, and it is prior art to this invention, a night time vision sensitivity testing simulator. This simulator includes the subject sitting behind the wheel of a sectioned car having a conventional windshield and driving interior. Through the windshield of the sectioned car, an observer views, projected by video or movie, a real world night driving scene. In my preferred embodiment I used a "country" night driving scene and a "city" night driving scene. The scenes are motion scenes with the driver seeing various road signs and hazards as if the car is proceeding at normal driving speeds (55 mph in the country and 35 mph in the city). To provide the equivalent of real world glare, I added glare sources to the simulator. Specifically, I attached small lights to the rear view mirror and the side view mirror. The solid angle of the source of the lights was maintained to produce an equivalent to an automobile headlight shining either through the side or rear view mirror. Naturally, this glare reproduced by reflection substantially the same glare as that of an on coming car.
Under these conditions, the effect of glare was measure by having the patient push a mechanical indicator whenever a road sign or hazard was identified. Upon pushing of the mechanical indicator, the sign or hazard was blanked out, and the patient asked to designate with particularity the sign or hazard observed. Sensitivity in the simulator was judged by the projected distance at which the subject undergoing test observed the sign or hazard.
Vision sensitivity was formerly measured with Snellen charts, the familiar randomly placed letters which diminish in size along graduated visual sensitivity lines. The subject in reading one line of larger letters can be graded 20/30, the next line of smaller letters 20/20, etc.
In U.S. Pat. No. 5,414,479 issued May 9, 1996 and U.S. Pat. No. 5,500,699 issued Mar. 3, 1996 both entitled Spatial Frequency and Contrast Sensitivity Test Chart and Method, I have shown that by using fine gradations of lines on a chart, contrast vision sensitivity can be more accurately determined. Additionally, and in U.S. Pat. No. 5,500,699 issued Mar. 3, 1996 both entitled Spatial Frequency and Contrast Sensitivity Test Chart and Method, I have shown that the background provided such images is necessary to avoid image artifacts that may otherwise be generated to provide in accurate or misleading test results. It will be understood that these issued patents form the preferred targets utilized with this disclosure, although the prior art Snellen tests or other low or high contrast vision sensitivity tests may be used as well.
Accordingly, these patents are incorporated by reference to this disclosure as if set forth herein in full.